The Worldwide Interoperability for Microwave Access Forum (WiMAX) has developed a specification that describes a radio interface for wireless data communications. This specification is known as the Institute of Electrical and Electronic Engineers (IEEE) 802.16e-2005 standard, and is incorporated herein by reference. This air interface is similar to Wireless Fidelity (WiFi) (also known as IEEE 802.11, including a, b and g versions) since a user device is connected wirelessly to an access point. However, WiMAX provides higher capacity, allows greater communications distances and provides mobility (access across different access points).
Users gain wireless connectivity in an access service network (ASN) via an access point (AP). WiMAX access points (also known as base stations) are similar to cellular access points, with each base station generally including a tower with antenna(s) situated that are locally controlled and include a base transceiver station (BTS) (sometimes also referred to as a base station controller). Once connected, users have the ability to roam from one access point (base station) to another access point.
Within the ASN, each BTS is connected (via wireless or wireline) to a controller node identified as a “gateway” (GW). Each gateway is generally responsible for controlling and communicating with a number of BTSs and is connected to a global network. Control and information relevant to a local BTS exists in the BTS. Control and information relevant to both the ASN of the end users and the BTSs exist in the gateway.
Within a WiMAX network, the ASN is broken down into functional pieces, for example, user security, accounting, mobility and quality of service (QoS). These functional entities reside or are located in the BTS, the gateway, or both. Thus, a functional entity may span both the BTS and gateway. For example, for accounting, an accounting agent exists on the BTS to monitor traffic locally. The agent reports statistics about a user's traffic behavior to the corresponding accounting controller on the gateway.
The definition of the functional entities (including peer applications of processes) and where they are located is defined by the WiMAX Network Working Group (NWG). WiMAX NWG has developed two draft documents describing various definitions and standards relating to the network system architecture for WiMAX networks, known as the (1) WiMAX End-to-End Network Systems Architecture, Stage 2 (Release 1, Aug. 8, 2006) and (2) WiMAX End-to-End Network Systems Architecture, Stage 3 (Release 1, Aug. 8, 2006), which are incorporated herein by reference. Stage 2 describes functional entities within the network while Stage 3 defines interfaces between functional entities.
Communication between each of the peer functional entities on the BTS and gateway takes place via an interface and architecture known as the “R6 reference point.” However, these documents do not fully define its operation and architecture. The Stage 2 and Stage 3 documents appear to define a distributed architecture for the R6 reference point, such that each functional entity operates independently, or almost independently, of each other. In this manner, an agent application in the BTS communicates directly with its corresponding control application in the gateway over a simple User Datagram Protocol (UDP) port. As such, a “peer application” (or process) is generally defined as including two portions or entities—a peer agent entity residing and executing within the BTS and a corresponding peer control entity residing and executing within the gateway, with these two entities communicating with each other. Each agent and corresponding control application may also be referred to by itself as a “peer application.” Each peer application or process utilizes both a special protocol header and yet-to-be defined standard messages. If a set of peer applications (i.e., together performing a main function in the ASN) requires either reliability or security, the set is required to build a protocol to provide this functionality between them. In addition, no mechanism is described or suggested for the BTS to discover the gateway, or vice versa, or to maintain state. For example, if a BTS is powered off or fails, the gateway has no indication of this event. Further, though keep-alive mechanisms have been suggested, this is on a per peer application basis with each peer application performing some keep-alive procedure. Having each peer application perform such a procedure results in duplication and increased overhead.
The WiMAX NWG Stage 2 or 3 documents do not provide any clear proposal relating to these issues for the R6 reference point. Initial descriptions therein indicate that there is no centralized application to assume any shared responsibilities. Rather, these responsibilities are distributed to each of the individual peer applications. With respect to reliability, due to the inclusion of different manufacturers trying to solve a given problem, a patchwork of solutions have been proposed. For example, some have defined an explicit acknowledgement for each message sent, while others have suggested a response with an implied acknowledgment, all within each specific peer application. Still others have not implemented any reliability.
Accordingly, there are needed methods and systems that provide a controller application for the establishment and maintenance of the R6 reference point (notably the R6 interface between the BTS and gateway ASN) within a WiMAX ASN, as well for providing discoverability and heartbeat communications therebetween.